I think the airlines (well both majors in Australia) are in the processes of reducing the main types in their fleet.
One only has to remember back to the AN days when the logistics of operating a multi Type, and widely diversified fleet became both unmanageable in some respects (B767 misguided SB interpretation
) etc. and subsequently uneconomic within the overall business model.
Ya all keep the faith now, and have a good 2016.
Regards, BE.